The value of surgery in removing or by-passing segmental areas of disease in the extra-cranial cerebral blood supply is well established.1-4 Delineation of such lesions by all available methods is important, because by their repair individuals are relieved of their intermittent cerebral deficit, and made less likely to have a brain infarct or stroke. Visualization of the occluding lesion provides the definitive diagnosis and is the essential guide to the type of surgery required. Despite numerous reports, it cannot be said that the literature contains clear guidelines as to the selection of patients for arteriography, or satisfactory conclusions as to the need of visualizing all parts of the extra-cranial arterial system in every patient as opposed to visualization of segments of it in certain patients.

It is our present purpose to evaluate the results of a conservative routine which stresses the use of percutaneous carotid arteriography and adds visualization